VLC Meeting Minutes- San Francisco

July 2009 IEEE P802.15-09-0538-00-0007 IEEE P802.15 Wireless Personal Area Networks

Project IEEE P802.15.7 Task Group Visible Light Communication (TG-VLC)

Title TG-VLC San Francisco July Plenary Meeting Minutes

Date 03 August 2009 Submitted [Taehan Bae] Voice: [+82-31-279-7293] Source [Samsung Electronics.Co., Ltd.] Fax: [+82-31-279-5130] [Suwon, Korea] E-mail: [[email protected]] Re:

Abstract Minutes of TG-VLC in San Francisco, CA, US.

Purpose Minutes of TG-VLC sessions

Notice This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

Release The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

TG-VLC Submission Page 1 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 Hyatt in San Francisco, CA US July 12 - 16, 2009

Tuesday, July 14, 2009 – Session 1

13:30-15:30 Meeting was called to order by Chair Eun Tae Won.

The IEEE patent policy was reminded by Chair Eun Tae Won and he asked whether there were any patent issues that needed to be raised. No patent issue.

Eun Tae Won remarked on the agenda for TG-VLC (15-09-0487-01-0007)

1. Meeting minutes was reviewed and approved (15-09-0443-00-0007) 2. Checked the schedule in agenda A. Notice this meeting schedule (6 time slots was allocated) B. Checked the presentation schedule

 There is a discussion for understanding the TCD. Bob explained the concept of the TCD and the reason that why we’re going to use TCD instead of TRD.

Soo-young: Can we use the term “proposal” or “contribution”?

Bob: Technical contribution is possible, it is easy to combine, relatively new, relatively fast and more flexible.

Sridhar: I think the partial proposal can be possible.

No objection and agenda was approved unanimously.

* Review result of interim conference call

* TCD 30 June 2009 Concall Minutes (15-09-0492): submitted by Sridhar Rajagopal (Samsung Electronics) / Rick Roberts (Intel) - TRC subcommittee Chair reviewed and informed the last conference call work.

* Hearing presentations

* About VLC using Arrayed PD/Image sensor (15-09-0502): presented by Tom Matsumura (VLCC)

Larry: At page 3, you said that you can distinguish the noise and the signal using the Image sensor. However, how can you say that the noise is the point source? If there is diffused noise, the image sensor can do that?

Tom: It’s for example, using the outdoor traffic signal.

Larry: I think if the noise is the point source, it can be distinguished, but if the noise is diffused, even the image sensor cannot distinguish it from the data signal. We need to consider the FOV

TG-VLC Submission Page 2 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 Rick: I have an objection about the 1:1 SNR at the PD. At page 2, you said that the sun is treated as DC level, and we need to use the sub carrier method. However, at page 3, figure 1’s explanation is not quite right. The band-pass filter is used.

Jason: At page 4, the contribution explained that the brightness is same and there is not limitation. But if we see the page 3, I think that it depends on the lens size.

Sridhar: page 2: the white LED seems not good for the high data rate, but I think Blue and yellow phosphor LED can be used for high data rate.

Clint: You should think it carefully. You need to consider the filter.

Taehan: VLCC only considers the sub carrier method for the modulation?

Tom: Because the baseband method is not good for the noise, we’d like to use the sub-carrier modulation.

Taehan: I know that. But I think SC modulation is not good for the high speed. So how much data rate do you expect?

Tom: 4.8kbps.

Soo-young: like at the conclusion page, do you think the PD limits the use case?

Tom: I think ISC is good for the low data rate application. VLCC thinks that VLC has more opportunity for low data rate application.

Soo-young: Do you have any idea for overcome the low data rate problem of ISC system?

Tom: We think a few M Byte can be possible.

Jimmy: At page 3, if there is sun light around a lot, can we distinguish?

Tom: Yes

Sridhar: I’m not sure the sun light make the PD saturate or not.

* Some comments on technical considerations document (15-09-0527): presented by Sang-Kyu Lim (ETRI)

- Sridhar: At page 8, I’m going to explain why we need it, that’s why I put those sentences.

- Sang Kyu: I expect we have more time to discuss for that on next session.

- Soo-young: We need common understanding. If the TCD is same as TRD, I don’t know why we need a TCD.

TG-VLC Submission Page 3 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 - Bob: Even if the contents are same, the word “consideration” can give us more flexible feeling compare the “requirement”. It looks very rigid. Anyway, it’s the guideline for the standard spec. - Soo-young: Do we have to follow that?

- Bob: It’s guideline.

- Dae-Ho: By the way, I think the “may” is more appropriate than the “should”.

- Bob: We can change the verb. I think we need to spend more time for making spec, not making the procedure.

* Some VLC System Issues (15-09-0522): presented by Rick Roberts (Intel) - Larry: At page 7, what’s the topology mean?

- Rick: Network topology.

- Larry: Based on application summary document, there are two types of topology. There is big difference between two of them. Considering the infrastructure give us a big difference in terms of MAC.

- Sridhar: I agree with the BER’s importance. However, for example, like the link budget, we need more other kinds of parameter.

- Rick: I agree with your opinion on the proposal point of view. Right now, I’m talking on the draft point of view.

- Sridhar: At the TCD, we’re not going to fix the number, because the TCD is the guideline. I think the proposal contributor should give the number for verification.

- Doug: At page 3, it’s only for the PHY? I think sometimes it depends on MAC.

- Rick: I agree.

- Soo-young: Do you have any specific reason for the simple MAC? Or special applications for that?

- Rick: We think the vehicle application.

- Larry: Sometimes, the simplest is the most complicated.

- Soo-young; Based on the application summary document, there are lots of applications. We’d better think more. Some application may need more complicated MAC.

- Taehan: At page 3, the optional beam steering is not included. How can we apply this part into the standard spec?

- Rick: It’s for the training. There is the training part in 802.15.3c.

- Taehan: Even if the FOV, PD is not for the standard you said, however do you need steering part for standard?

- Rick: In 802.15.3c, there is the method to find the signal position using the training sequence. That’s what I’m saying.

- Sang-kyu: I think the light source intensity should be included. It depends on applications.

TG-VLC Submission Page 4 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007

Recessed by Chair Eun Tae Won.

Recess until session 2

Tuesday, July 14, 2009 – Session 2

 VLC Technical Consideration Document sub-committee discussion (Sridhar Rajagopal / Samsung)

* Resolving device characteristics comments for TCD (15-09-0507)

- Sridhar informed the result from the last conference call and introduced three options for the “device characteristic” on TCD

- There is a discussion for the “Device characteristic” on TCD.

- Rick: I prefer the option 2. It’s good for verifying the performance and calculating the link budget.

- Tom: I prefer the option 3. We need the some guideline.

- Taehan: I like the option 1. Usually, the standard spec does not include the RX part. However, we need the guideline of the TX part.

- Sang-kyu: I also prefer the option 1. I think the option 1 is more appropriate.

- Tom: The FOV is included?

- Taehan: No.

- Sridhar: Everyone seems agree that we don’t need the RX part on TCD. So, I’m going to delete RX part on table. - Sridhar: We need to discuss more for the table.

- Rick: Why don’t we delete the table and take care of those things on the technical contribution later for link budget. - Soo-young: Every proposal has own different number. If so, how can we compare each other?

- There is more discussion for the “table in the Device characteristic” on TCD.

- Finally everyone agree with current version on section 6.

 Rick is going to calculate the link budget and offer to VLC committee.

* Resolving TCD Comments in 15-09-0466-00-0007 (09-0506) - Soo-young submitted the comment document (15-09-0466) for the TCD.

TG-VLC Submission Page 5 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 There is a discussion, review and resolution for each comment.

- The Chair (Eun Tae Won) asked the 10 minutes extension for completing the resolution. Everyone agree.

Recessed by the Chair Eun Tae Won.

Wednesday, July 15, 2009 – Session 3

13:30-15:30

Meeting was called to order by Chair Eun Tae Won.

Eun Tae Won remarked on the updated agenda for TG-VLC.

* Hearing presentations

* Physical layer proposal outline (15-09-0550): Presented by Taehan Bae (Samsung Electronics)

- Rick: Could you tell me how can you use the “band plan”?

- Taehan: We going to explain more next MAC consideration presentation.

- Rick: I’d like to know some case like 3 channels sending the same data.

- Sridhar: Like the MIMO, it’s the same as each channel send own different data.

- Sang-kyu: How about using the PD responsivity?

- Taehan: I think that’s good idea. By the way, there are different types of PD. We not sure which type we need to use it.

- Taehan: Non-liner channel band assignment is the idea concept.

- Rick: Do you think the modulation affect the bandwidth plan?

- Taehan: I don’t understand what relationship is between two of them.

- Soo-young: I think some modulation scheme need to use the whole band.

- Taehan: Which modulation scheme is that? I’m not sure.

- Soo-young: I don’t know yet.

- Taehan: We can discuss later for that.

- Sany-kyu: The forward current caused shifting the wavelength?

- Taehan: Yes, That’s why we need to guard color. It prevent the interference each adjacent color.

- Jimmy: Do we need to consider the LED Manufacturer?

- Taehan: At page 11, that figure is from the current available commercial LED spectrum figure.

* VLC MAC Considerations based on TCD (15-09-0549): presented by Ying Li (Samsung Electronics)

Rick: At page 12, as you know Intel has considered the vehicle application. I don’t think your message flow is not good for the high speed vehicle.

Ying: I think it’s going to be low data rate.

Rick: Now, I understand the band plan. By the way, if we have 3 colors, we can make every other color. Why we need to fix the band?

Soo-young: Do you consider only blue phosphor LED? If RGB LED is considered, I don’t think we need guard band

Sridhar: It’s not mean that every color needs to have it.

Jimmy: How about the packet structure?

Ying: We think a kind of indicator.

Doug: In your message flow chart, you mentioned the TDD. Do you consider the collision detection mechanism?

Ying: TDD or FDD could be happened.

Doug: TDD scheme is not proper to the CSMA.

Sridhar: I think it depends on application.

Yeong Min: How many channel you expect?

Ying: We expect 7 now, however, it depends on band plan. It could be 13 like Taehan said before. We don’t know yet.

Yeong Min: How many nodes we talking now?

Taehan: Based on TCD, we don’t have limit.

Yeong Min: At page 16, how about the bandwidth and resource allocation?

Ying: We don’t have any limitation of VLC application.

* Line coding performance in wireless optical channel (15-09-0526): presented by Jaeseung Son (Samsung Electronics)

Rick: What’s the optical line coding?

TG-VLC Submission Page 7 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 Jaeseung: It’s general line coding method.

Rick: For vehicle’s case, the dimming is problem. I’d like to minimize the light dimming and maximize the energy bit. I also like to see the spectrum for checking the interference.

Sang-kyu: Why did you using the optical channel?

Jaeseung: If possible, we’d like to have a real optical channel.

Jimmy: The negative signal can be possible?

Jaeseung: No.

Jae Sang: At page 14, it seems not for mobile environment. 2nd tab is too good.

Jaeseung: Because this is from very LOS condition.

Jae Sang: I still don’t know about the VLC channel model.

Jaeseung: If you see my old contribution, you can find that the real test result and the simulation result is almost same.

* Selection of VLC application (15-09-0528): presented by Dae-Ho Kim (ETRI)

Rick: Basically, I agree with your idea. By the way, any range you selected we need to show the link budget. Image sensor’s case, it’s not easy to calculate the link budget.

Myunghee: Why we need a vehicle to vehicle communication?

Dae-Ho: It’s from the application summary document.

Myunghee: I think the 100kbps is enough for the vehicle to infrastructure communication. However, the communication between vehicle to vehicle need at least 10Mbps. We also need to consider the mobility.

Wednesday, July 15, 2009 – Session 4

Tae-Guy: Why don’t you change the document name the TRD into TCD?

Sridhar: I’d like to keep the history to update the file. By the way, if it’s done, I’ll change.

Jimmy: The regulation written in TCD is not correct.

Taehan: We need to wail and verify the safety regulation you mentioned.

Sridhar: Why don’t you research that regulation and have a presentation on tomorrow.

There is a long discussion for Table 5 on TCD.

After long discussion, Sridhar want to know the committee’s opinion using the straw-poll

Option 1: Do not change table 5. Option 2: change table 5, based on contribution. Option 3: change table 5, based on general agreement in the group Option 4: Don’t care

After discussion about options, change the option

Option 1: Do not change table 5. (12) Option 2: allow change to table 5. (6)

Straw poll result: option 1 (12): option 2 (6)

Based on the result, keep the table 5.

There is a discussion about the IEC 60825 and the eye safety issue. It’s going to continue tomorrow on Regulatory document subcommittee.

Thursday, July 16, 2009 – Session 5

08:00-10:00

Meeting was called to order by Chair Eun Tae Won.

* Hearing Presentation

* VLC Coexistence with lighting control (15-09-0557-01): presented by Soo-young Change (CSUS)

Rick: Who can do the LAL?

Soo-young: I think we can do it.

Rick: Is there anyone who has talked with LED vendor person? I think that’s the problem.

Soo-young: I agree. I have studied before and I think we need to have simple control.

Rick: We need to consider the power supply for LED driving.

There is a discussion for the VLC system structure.

 VLC Regulatory Document sub-committee discussion (Tae-Gyu Kang / ETRI)

* A progress status of IEEE 802.15.7 VLC regulations document (15-09-0563)

- Report to VLC member the regulatory document progress.

* Change in Japan’s energy saving law 2009 (15-09-0546): presented by Tom Matsumura (VLCC)

Rick: I know you’d like to talk about the LED proliferation. However, VLC can affect the LED efficiency. That might be the problem.

Tae-Gyu: Thank you for the presentation. I’ll put your presentation into the Regulatory document.

Sang-Kyu: Do you have any kind of project related with LED deploy?

Tom: No.

Soo-young: I don’t understand that what kind of relation with VLC.

Tom: I think it related with the LED infrastructure proliferation.

* Relevant eye safety standards (15-09-0561): presented by Jimmy Chau (Boston University)

Tae-Gyu: Thank you for the presentation. I don’t think we don’t need to change the regulation on TCD.

* IEEE 802.15.7 VLC Regulation document configuration (15-09-0202-02): presented by Tae-Gyu Kang (ETRI)

Tae-Gyu: I’d like to complete this document on next meeting.

 Rick is going to prepare the information about USA regulation related with VLC.

Eun Tae: How about the Japan regulation?

Tom: We have JIS and it’s similar to IEC regulation.

Eun Tae: If possible, I’d like to include the Japan’s regulation.

* TG7 Technical Considerations Document (15-09-0564)

There is a discussion about the Topology (P2MP) and multicast.

TG-VLC Submission Page 10 Taehan Bae July 2009 IEEE P802.15-09-0538-00-0007 Recessed by Chair Eun Tae Won.

Thursday, July 16 – Session 6

* Rick Roberts moved to approve the TCD (15-09-0564) with Taehan Bae seconding the motion. * Motion was approved. Approval / objection / abstain: 12 / 0 / 0

Eun Tae Won announced that TG-VLC need to have a technical editor team. Anyone wants to be a technical editor need to send mail to Chair.

Adjourn by Chair Eun Tae Won.

TG-VLC Submission Page 11 Taehan Bae